The Basics
What is...
What is...
This and That
100
Why do we use machines?
To reduce the amount of effort or work we exert and to increase our ability to lift or move objects.
100
a ramp?
It helps us move heavy objects more easily but we have to move them further to complete the task. We use stairs or ramps to walk up and down. Stairs cut into the incline to make it easier to walk up a steep incline.
100
A Lever?
The lever is a bar that turns on a point called a fulcrum. The secret of the lever is the increased distance over which the force moves, i.e., the arm length of the lever, which is determined by the position of the fulcrum (pivot). It is the same principle as the inclined plane - the greater the distance over which the force must be applied, the smaller the force required to do the work (lift the load). Our arm is in fact a lever. How hard it would be to use the arm if it didn't bend at the elbow! The elbow acts as a fulcrum and the muscles between the elbow and shoulder provide the force (hence the lower arm becomes the lever). Imagine that you have a caston your arm so you can't move your elbow. Now try lifting a bag of flour. Which is easier, with or without the cast?
100
What simple machines are in the inclined plane family?
Wedge, Ramp and Screw
200
Why do we use simple machines?
They make work easier by enabling us to use less mechanical effort to move an object.
200
Friction?
Friction is the resistance produced by rubbing two objects together.
200
What kind of simple machine is a screw?
What is a wedge?
200
What simple machines are in the lever family?
Lever, Wheel and axle, pulley.
300
What are the two families of simple machines?
The inclined plane familyy and the lever family.
300
A wedge?
Consists of two back to back planes. It looks like an inclined plane but works differently. It can hold things together, such as a doorstop or nail or it can split things apart like an axe or chisel.
300
This is produced by rubbing two objects together.
What is Friction?
300
We use these to reduce the amount of effort or work we exsert.
What is Machines.
400
What are the six classes of machines?
Wedge, ramp, screw, lever, wheel and axle, pulley.
400
A Screw?
The ridges are called the thread of a screw. These threads cut a groove in the wood as you turn the screw, making it hold very tightly. To remove a screw you have to turnin theopposite direction with a screwdriver. It is very difficult to remove a screw by pulling it straight out. The distance between the threads depends on the slope of the inclined plane - the steeper the slope, the wider the thread. Screws with less distance between the threads are easier to turn. As with any inclined plane used as a simple machine, the force required is less but the distance travelled is greater
400
Where is the fulcrum located on a Wheelbarrow? a shovel? a bat?
A Wheelbarrow - at the wheel. A Shovel - mid-point of the handle. A Bat - at the base of the handle.
400
This helps us move heavy objects more easily but creates a further distance to move them.
What is a ramp.
500
How are the classes of simple machines grouped?
Incline Plane Family - wedge, ramp, screw Lever Family - lever, wheel and axle, pulley
500
Our arm is this type of simple machine.
What is a lever.
500
What is a wheel and axle?
It is a lever that is able to rotate through a complete circle of 360 degrees. The circle turned by the wheel is much larger than the circle turned by the axle, which moves a shorter distance. The increased distance over which force is applied as the wheel turns results in a more powerful force on the axle which moves a shorter distance.
500
Name the two families of simple machines.
They are the inclined plane family and the lever family.
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